Piston



y 1940. A. LQNELsoN 2,200,966

rxsmou Original Filed June 2, 1934 INVENTOR,

Patented May 14, 1940 2,200,966

UNITED STATES PATENT OFFICE.

PISTON Adolph L. Nelson, Detroit, Mich, assignor to Bohn Aluminum &Brass Corporation, Detroit, Mich, a corporation of Michigan Originalapplication June 2, 1934, Serial No. 728,663. Divided and thisapplication March 24. 1937, Serial No. 132,681

2 Claims. (01. 309-43) The present invention relates to an improved andthe inner wall of the ring ll provides a conpiston, and particularly toa light-weight piston tinuous contour. A slot 13 extends verticallyadapted for use in internal combustion engines. 'through thrust face 12and forms two separated The invention provides a piston in which thewings l4 and IS. The lower end of this slot-is 5 piston skirt is formedwith a vertical slot and circuitously arranged so as to form a hook I6 5with a part that extends across one end of the attached to wing l4 andhook l1 attached to slot and arranged to prevent spreading of the 'wingHi. The inner faces of these two hooks enslot when a lathe or grindercenter is inserted gage each other as illustrated to prevent spreadinthe open end of the piston and to permit ining of the lower end of theskirt, but extra clear- 10 ward yielding of the skirt when pressure iscreance is provided as shown to permit movement of 10 ated between theskirt and the cylinder in which the wings l4 and i5 toward each other tonarrow the piston is operated. the slot [3. This application is adivision of my applica- When a piston constructed in this manner is tlonSerial No. 728,663, filed June 2, 1934. placed on lathe or machinecenters, one center While preferred forms of the invention are engagesthe head of the piston and a tapered cen- 15 disclosed herein forpurposes of illustratiom variter is pressed inside the lower open end ofthe ous changes may be made in the structure withpiston. This taperedcenter would, in the about departing from the spirit of the invention.sence of the restrictor, spread the slot l3 and en- In the drawing:large the lower end of the skirt, thus interfering Figure l is a sideelevation of a piston emwith accurate finishing of the piston. But the20 bodying the invention. presence of the restrictor prevents any suchFigures 2 and 3 are views similar to Figure 1 spreading of slot I3. butshowing modified forms of the invention. On the other hand, the pistonis yielding so The invention can be applied to any preferred far asconcerns the cylinder in which it is later type of piston, and in thespecies of Figure 1 it assembled. Whenever the cylinder exerts pres- 25is shown applied to a piston of the type illustrated sure on the skirtof the piston, as when a rise in in Nelson Patent No. 1,830,172 in whichthe extemp ra causes the piston to xp faster, pension of the skirt iscontrolled by steel struts. than the cylinder, the restrictor does notinter- In these figures the piston includes the head fere with theclosing-in or narrowing of the slot H), a lower ring II and a thrustface I! which exl3. 30 tends upwardly from the lower ring. In Figure 2the restrictor is a ring I8 that has The invention is'particularlyadapted for use a snug fit w t Sides f a Ve- T ends 0! on pistons formedof light-weight material, such the ring ov p a have hooks l9 and 20 thatas aluminum alloy. Pistons formed of these macoop ra i a m r similar tothe hooks of terials usually have a higher rate of thermal Fi expansionthan the cylinders in which they are The rest c o 2| of Figure 3 is amember that used'an'd theyshould be constructed so they will lies in agroove and is flush with the outer face not slap when cold nor seizewhen hot. It is a f t e Sk t T e d heads 22 engage in common practice toprovide such pistons with a e e s in the Skirt t D L Clearance 40vertical slot which permits the skirt to yield ciryond the ends of theheadsfl to permit the skirt 40 cumferentially as it expands into contactwith 0 yield d i" the cylinder wall. One drawback in the use of Any ui lm a f x mp steel. can such vertical slots is that if the slotted pistonis be used for the restrictors. placed on centers for a finishingoperation, such I claim:

as grinding or boring the piston pin holes, the A piston comprising ahead, a Skirt with a 45 skirt spreads and is therefore in a distortedconslot extending vertically therein and forming two dition during thefinishing operation. I separated wings, a hook member formed oneachAccording to the present invention a restrictor 0 Sa d Wings, d hookmembers being erpart extends across at least one end of the slot,engaged to prevent spreading of the slot when a so the restrictor partbeing arranged to prevent outlathe center is placed within the open endof the ward yielding but to permit narrowing of the piston, the skirtbeing provided with clearance slot under pressure. which permits closingin of the slot when pressure In the preferred construction illustratedin is created betweenthe skirt and the cylinder in Figure 1 the lowerring ll continues uninterwhich the piston is operated. ruptedly aroundthe circumference of the skirt, 2. A piston comprising a head, a skirtwith a ll t'wo separated wings, each wing provided with a is createdbetween the skirt and the cylinder in hook member, said hook membersbeing interwhich the piston is operated. 5 engaged to prevent spreadingof the slot when a lathe center is placed within the open end of theADOLPH L. NEUSON.

slot extending vertically therein, the lower end piston, the beingprovided with clearance I of the slot being circuitously arranged toprovide which permits closing in of the slot when pressure,

